Submarine avalanches, known as turbidity currents, have been found to carry microplastics—tiny plastic particles—to the deep ocean floor, according to recent research. These underwater flows occur in coastal areas and especially near estuaries, where rivers meet the sea. They can travel hundreds of kilometers at speeds up to 20 km/h, carrying sediments and, surprisingly, significant amounts of microplastics along with them. These currents act like highways, transporting microplastics as deep as 3,000 meters below the ocean's surface. Studies in the Tyrrhenian Sea and the Whittard Canyon, located 300 kilometers off the British coast, found that areas rich in plastics often align with the main paths of these deep-sea currents. This discovery challenges the previous belief that plastics sink directly downward after being carried by surface currents. A study published in 2025 confirmed that in the Whittard Canyon, turbidity currents serve as primary routes for microplastic transport. Researchers from the Laboratoire énergies et mécanique théorique et appliquée (LEMTA) at the University of Lorraine in Nancy and the Laboratoire de physique at the ENS de Lyon conducted experiments to track how microplastics move along the ocean floor. Their findings suggest that the swirling motion of the currents pushes the particles downstream. This has important consequences for marine ecosystems and, ultimately, human health, as microplastics tend to accumulate in biologically rich areas, potentially entering the food chain. In addition to microplastics, turbidity currents also transport nutrients and organic matter that support deep-sea ecosystems. Understanding the physics behind these currents is crucial for predicting how plastics will move through the ocean and for protecting these fragile environments. This research highlights the complex interactions between human-made pollutants and natural ocean processes.